Gas injection systems for optimizing nanobubble formation in a disinfecting solution

ABSTRACT

Systems, devices, and methods are presented for optimizing the formation of gas nanobubbles in a disinfecting solution. In an example system for treating contaminated water, a centrifugal pump draws the water from a reservoir and circulates the water in and through a circuit of elements including a mixing chamber in the pump, a pressure vessel, a backflow valve, a Venturi injector, and a pair of nozzles immersed in the reservoir. The system injects ozone-rich gas into the fluid to produce an aqueous solution containing a volume of gas nanobubbles. The nozzles release the gas nanobubbles into the reservoir, creating highly reactive compounds that destroy organic compounds and other contaminants in the water.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/832,308, filed on Mar. 27, 2020, entitled “GAS INJECTIONSYSTEMS FOR OPTIMIZING NANOBUBBLE FORMATION IN A DISINFECTING SOLUTION,”which claims the benefit of and priority to both U.S. ProvisionalApplication No. 62/825,491, filed Mar. 28, 2019, entitled “BackflowDevice for Optimizing the Formation of Nano-bubbles in a Fluid,” andU.S. Provisional Application No. 62/969,729, filed Feb. 4, 2020,entitled “Systems and Methods of Infusing Nano-bubbles of Enriched Gasinto a Fluid to Create a Solution for Removing Pollutants,” each ofwhich is incorporated herein in its entirety.

TECHNICAL FIELD

Examples set forth in the present disclosure relate to the field of airand water treatment systems. More particularly, but not by way oflimitation, the present disclosure describes methods and systems foroptimizing the formation of gas nanobubbles in a disinfecting solution.

BACKGROUND

Conventional water treatment systems use a variety of chemicals, most ofwhich are not environmentally friendly, to remove microbial toxins andpathogens. Treating large bodies of open water such as lakes, ponds, andlivestock waste pools is currently too expensive and not technologicallyfeasible. Untreated waste often includes large amounts of methane,nitrogen, and other substances that raise concerns about environmentalimpact. Ballast water released from cargo ships can contaminate bays andinlets around ports. Concern is also increasing about the threat ofterrorist activity that might be directed toward the water supply, aswell as natural water sources and environments. Existing systems fordisinfecting and sterilizing the air in a room, surfaces, medicalequipment, and other components are expensive, time-consuming, and inmany cases are not fully effective. Many types of microbes andpathogens, including viruses, can survive on surfaces and in enclosedspaces for a lengthy period of time unless treated.

BRIEF DESCRIPTION OF THE DRAWINGS

Features of the various implementations disclosed will be readilyunderstood from the following detailed description, in which referenceis made to the appending drawing figures. A reference numeral is usedwith each element in the description and throughout the several views ofthe drawing. When a plurality of similar elements is present, a singlereference numeral may be assigned to like elements, with an addedlower-case letter referring to a specific element.

The various elements shown in the figures are not drawn to scale unlessotherwise indicated. The dimensions of the various elements may beenlarged or reduced in the interest of clarity. The several figuresdepict one or more implementations and are presented by way of exampleonly and should not be construed as limiting. Included in the drawingare the following figures:

FIG. 1 is a schematic illustration of a gas-injection system, accordingto an example implementation;

FIG. 2A is a schematic view of a pressure vessel suitable for use withthe gas-injection system of FIG. 1;

FIG. 2B is a perspective illustration of a deflector, according to someexample implementations;

FIG. 3A is an illustration of a backflow valve assembly with a manualcontrol, according to some example implementations;

FIG. 3B is an illustration of a backflow valve assembly with motorizedcontrol, according to some example implementations; and

FIG. 4 is an illustration of a nozzle, according to some exampleimplementations.

DETAILED DESCRIPTION

The present systems and apparatuses and methods are understood morereadily by reference to the following detailed description, examples,and drawings. The terminology used herein is for the purpose ofdescribing particular aspects only and is not intended to be limiting.

Like parts are marked throughout the following description and drawingswith the same reference numerals. The drawings may not be to-scale andcertain features may be shown exaggerated in scale or in somewhatschematic format in the interest of clarity, conciseness, and to conveyinformation.

The following description is provided as an enabling teaching in itscurrently known embodiment. To this end, those skilled in the relevantart will recognize and appreciate that many changes can be made to thevarious aspects described herein, while still obtaining the beneficialresults. It will also be apparent that some of the desired benefits canbe obtained by selecting some of the features described withoututilizing others. Accordingly, those who work in the art will recognizethat many modifications and adaptations to the examples described arepossible and can even be desirable in certain circumstances and are apart of this disclosure. Thus, the following description is provided asillustrative of the principles and not in limitation.

As used throughout, the singular forms “a,” “an” and “the” includeplural referents unless the context clearly dictates otherwise. Thus,for example, reference to a component can include two or more suchcomponents unless the context indicates otherwise.

Ranges can be expressed herein as from “about” one particular valueand/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint.

As used herein, the terms “optional” or “optionally” mean that thesubsequently described event or circumstance may or may not occur, andthat the description includes instances where said event or circumstanceoccurs and instances where it does not.

As used herein, the term “facilitate” means to aid, assist, or makeeasier. The term “inhibit” means to impede, interfere with, hinder, ordelay the progress.

As used herein, the terms “proximal” and “distal” are used to describeitems or portions of items that are situated closer to and away from,respectively, another item or a user. Thus, for example, the far end ofa pipe attached to a vessel may be referred to as the distal end becauseit is far away relative to the vessel.

The terms “coupled” or “connected” as used herein refer to any logical,optical, physical, or electrical connection, including a link or thelike by which the electrical or magnetic signals produced or supplied byone system element are imparted to another coupled or connected systemelement. Unless described otherwise, coupled or connected elements ordevices are not necessarily directly connected to one another and may beseparated by intermediate components, elements, or communication media,one or more of which may modify, manipulate, or carry the electricalsignals.

The term “nanobubble” as used herein refers to and includes bubblediameters between about ten nanometers and about four hundred microns. Ananometer is one billionth of a meter (1.0E-9 meter). A micron ormicrometer equals one millionth of a meter (1.0E-6 meter).

A solution is a liquid mixture in which a minor component, called asolute (such as an enriched gas) is dissolved into a major component,called the solvent (such as water, for aqueous solutions). The quantityof solute that can be dissolved into a solvent varies, depending onseveral factors such as temperature and the solubility of the solute.The capacity of a solute to be dissolved in a solvent is known assolubility. Solubility is a chemical property of the solute and does notchange.

A solution is saturated when it contains the largest possible quantityof the solute (such as enriched gas) that can be dissolved into thesolvent under normal conditions. Special conditions, such as kineticmixing, injection at higher pressures, higher temperatures, and/or forlong durations, are typically required in order to inject additionalsolute into the solvent. The forced addition of more solute, in somecases, produces a solution. A solution of gases in a liquid willtypically form bubbles. Carbonated water is an example of an aqueoussolution supersaturated with carbon dioxide gas.

The term “injected” as used herein means and refers to the forcedinjection of additional gas (solute) into the fluid (solvent) which,under some conditions, produces a supersaturated solution. The term“released” as used herein refers to the opposite process, during whichgas bubbles that were once dissolved in a fluid solution areun-dissolved or released.

Additional objects, advantages and novel features of the examples willbe set forth in part in the following description, and in part willbecome apparent to those skilled in the art upon examination of thefollowing and the accompanying drawings or may be learned by productionor operation of the examples. The objects and advantages of the presentsubject matter may be realized and attained by means of themethodologies, instrumentalities and combinations particularly pointedout in the appended claims.

Although the various embodiments and implementations are described withreference to an example system for optimizing bubble size andconcentration in a fluid mixture to improve its usefulness indecontamination applications, the systems and methods described hereinmay be applied to and used with any of a variety of other systems.

Reference now is made in detail to the examples illustrated in theaccompanying drawings and discussed below.

FIG. 1 is a schematic illustration of a gas-injection system 1000,according to an example implementation. The system 1000 includes acentrifugal pump 200 for circulating a in and through a circuit ofelements, wherein each element is in fluid communication with the next.The circuit of elements, in this example, includes the centrifugal pump200, a pressure vessel 300, a backflow valve 500, a Venturi injector600, and a pair of nozzles 700 a, 700 b immersed in the reservoir 10 ofcontaminated fluid. The contaminated fluid may be water, saltwater,another liquid, or a gas in fluid state, such as air. The circuit ofelements is monitored, adjusted, and controlled by a control unit 100,as described herein. The circuit of elements is closed, recirculatingthe fluid for treatment until a desired quantity of pollutants isremoved from the fluid. The term pollutant is used herein in itsbroadest sense, to include any of a variety of substances to be removedfrom the fluid.

The system 1000 also includes a gas supply, which may supply one or moregases (e.g., ozone, oxygen, hydrogen). The gas supply, in someimplementations, includes one or more oxygen concentrators 110 a, 110 bfor converting ambient air into an oxygen-enriched gas. Some types ofoxygen concentrators can process about thirty liters per minute andgenerate an oxygen enrichment of about ninety-two percent. Largerconcentrators and other equipment can be used to scale-up the systemthat handle larger volumes of fluids and gases. The gas supply alsoincludes one or more ozone generators 120 a, 120 b for converting theoxygen-enriched gas into an ozone-rich gas. The ozone-rich gas entersthe circuit of elements at the pump 200 and at the Venturi injector 600.The system 1000 also includes an ozone destructor 400 for capturingexcess ozone and converting it to oxygen. In other exampleimplementations, one or more different gases may be used. For example,the system may first infuse an ozone-rich gas to clean a reservoir ofwater, followed by an injection of oxygen-rich gas to remove any excessozone, followed by an injection of additional oxygen and/or hydrogen toincrease the concentrations of such gases in the water and therebycreate a drinking water that is infused with such gases.

The centrifugal pump 200 includes a mixing chamber 205 where thecontaminated fluid mixes with a gas (e.g., an ozone-rich gas). Thecentrifugal pump 200 includes one or more drive rotors called impellersinside the mixing chamber 205 to promote mixing and facilitate theinjection of gas into the fluid. In a centrifugal pump 200, the fluidenters the mixing chamber 205 near the center of the rapidly rotatingimpellers, which force the fluid by centrifugal force outwardly (i.e.;radially, relative to the center of the impellers). In an alternativeimplementation, the mixing chamber 205 includes one or more gears, pairsof gears, or other agitators to promoting mixing. The gas enters themixing chamber 205 under relatively high pressure, causing the gas todissolve in the fluid, which causes bubbles to form. Controlling thevolumes and pressures of fluid and gas facilitates the formation ofsmaller and smaller bubbles, some of which are nanobubbles. The gassupply, as shown, injects a first quantity of gas into the fluid, insidethe mixing chamber 205, to produce a first solution. The first solutionmay or may not be fully saturated with gas. The first solution containsa first volume of gas nanobubbles.

The gas flows to the pump 200 through a gas inlet tube 140, which mayinclude a first control valve 540. The contaminated fluid flows to thepump 200 through an inlet pipe 210, which may include an inlet valve 510for controlling the flow from the reservoir 10. The inlet valve 510 alsoprevents fluid from draining out of the reservoir 10 when the system1000 is not in use. The inlet pipe 210 may also include a priming pump(not shown) for initiating the flow of fluid into the circuit, which isparticularly useful when the system starts to operate. The inlet pipe210 and other pipes carrying the fluid may be made of PVC, flexiblehose, or another suitable material capable of withstanding the pressuresand temperatures of the system 1000.

The pressure vessel 300 is mounted above the pump 200 in this example.The pressure vessel 300 is configured to receive the first solution fromthe pump 200, and hold the first solution under an internal pressure,and for a selected duration. The pressure and duration are set,adjusted, and controlled by the control unit 100. The combination ofpressure and time facilitates the additional injection of gasnanobubbles—both inside the pressure vessel 300 and inside the mixingchamber 205, due to the backflow pressure generated by the pressurevessel 300. The combination of pressure and time produces a secondsolution, which contains a second volume of gas nanobubbles (in additionto the first volume injected inside the mixing chamber 205 of the pump200.

The second solution, in some implementations, exits the pressure vessel300 and flows through the outlet pipe 220 to a pair of nozzles 700 a,700 b which are configured to spray the second solution into thereservoir 10. As shown in FIG. 1, the Y-shaped splitter pipe may besymmetrical in order to evenly divert the flow into the pair of nozzles700 a, 700 b. Like the pressure vessel 300, the nozzles 700 a, 700 bgenerate a backflow pressure into the system, which facilitates theadditional injection of nanobubbles in the elements located upstream.The nozzles 700 a, 700 b are spaced apart from one another and immersedin the reservoir 10 to a depth located at a mean height 730 above thereservoir floor 20. The nozzles 700 a, 700 b, in some implementations,are suspended above the reservoir floor 20 by one or more floats andcounterweights (not shown), especially in environments subject to tidalchanges or other volume-related fluctuations. The nozzles 700 a, 700 bare sized and shaped to release a portion of the volumes of gasnanobubbles into the fluid in the reservoir 10. The release of thenanobubbles injects the gases that were dissolved in the secondsolution. For implementations in which the gas is an ozone-rich gas, therelease of nanobubbles creates hydroxyl radicals which are highlyreactive and useful in destroying organic compounds and othercontaminants.

The second solution, in another example implementation, exits thepressure vessel 300 and flows through an outlet pipe 220 to a backflowvalve 500 before flowing into the nozzles 700 a, 700 b. The backflowvalve 500 is positioned within the outlet pipe 220 and is constructedand otherwise configured to selectively restrict the flow of the secondsolution through the outlet pipe 220. By restricting the flow throughthe outlet pipe 220, the backflow valve 500 generates a significantbackflow pressure in the system, which facilitates the additionalinjection of nanobubbles in the elements located upstream. The backflowpressure increases the internal pressure inside the pressure vessel 300and prolongs the duration of time for mixing inside the pressure vessel300. The backflow pressure, to some extent, also affects the pressureand mixing time inside the mixing chamber 205 of the pump 200. Thecombination of increased pressure and a longer mixing time causes thepressure vessel 300 to produce a third solution, which contains a thirdvolume of gas nanobubbles (in addition to the first volume injectedinside the mixing chamber 205 of the pump 200, and in addition to thesecond volume injected inside the pressure vessel 300 in a system thatdoes not include a backflow valve). After passing through the backflowvalve 500, the third solution is injected into the reservoir 10 throughthe nozzles 700 a, 700 b as described herein.

The system 1000 illustrated in FIG. 1 also includes a circuit forrecirculating the solution back into the centrifugal pump 200. As shown,a recirculation pipe 230 is configured to deliver a selected portion ofthe solution from the outlet pipe 220 and back into the inlet pipe 210.The recirculation pipe 230 includes a recirculation valve 520 to controlthe flow; in other words, to control the selected portion of thesolution to be recirculated. The recirculation pipe 230 includes aVenturi injector 600 which, as the name suggests, is sized and shaped tocreate the Venturi effect as the solution flows through it. The Venturiinjector 600 includes a suction port in the side wall of the lengthwisechamber through which the solution flows. A supplemental gas inlet tube130 is connected to the suction port and configured to carry theozone-rich gas. The gas inlet tube 130, in some implementations, doesnot include a control valve, instead relying on the suction generated bythe Venturi injector 600 to draw gas through the inlet tube 130. The gasvalve 540 in the gas supply tube 140 to the pump 200 can be adjustedwhen the Venturi injector 600 is operating, in order to balance thesupply of gas.

The lengthwise chamber is sized and shaped to create a pressuredifferential, which is sufficient to draw a supplemental quantity of gasthrough the suction port and into the selected portion of the solution.The injection of supplemental gas produces a fourth solution, whichcontains a fourth volume of gas nanobubbles (in addition to the firstvolume injected inside the mixing chamber 205 of the pump 200, and inaddition to the second volume injected inside the pressure vessel 300).The fourth solution next flows into the main inlet pipe 210 and backinto the centrifugal pump 200 for additional mixing and injection ofadditional gas.

The system 1000, in some implementations, may deliver the ozone-rich gaseither (a) through the inlet tube 140 only, directly into thecentrifugal pump 200, (b) through the supplemental gas inlet tube 130only, directly into the Venturi injector 600, or (c) through both inlettubes 140, 130—in which case the pump 200 and the Venturi injector 600cooperate to improve the quality and quantity of nanobubbles in thesolution.

The control unit 100 is connected and configured to set, monitor,adjust, and otherwise control the system 1000, as described herein,including the gas supply, the centrifugal pump 200, the pressure vessel300, the backflow valve 500, the Venturi injector 600, and the oxygendestructor 400, as well as the valves located in the piping and tubingthat connects the elements of the system 1000.

For example, the control unit 100, in some implementations, controls theoxygen concentrators 110 a, 110 b, the ozone generators 120 a, 120 b,and the gas valves 530, 540 that control the flow of gas in the system1000. The control unit 100 controls the speed of the motor driving thepump 200, the internal pressure inside the pressure vessel 300, thebackflow valve 500, and the Venturi injector 600, as well as the fluidvalves 510, 520 that control flow of fluid in the system 1000.

By and through its connections to the system 1000, the control unit 100also gathers and stores information about flow velocities, pressures,temperatures, and other conditions. By adjusting the valves and otherelements in the system 1000, the control unit 100 balances the flowvelocities, pressures, and temperatures between and among the systemelements in order to optimize the generation of nanobubbles. In thisaspect, adjustments to the system parameters made by the control unit100 cause the system 1000 as a whole to generate a larger quantity andconcentration of nanobubbles, a higher quality of nanobubbles, and amore stable solution at various stages throughout the circuit so thatthe nanobubbles are retained in solution until they reach the nozzles700 a, 700 b.

The control unit 100, in some implementations, includes a programmablelogic controller (PLC) that operates and controls a power supply, timersand counters, a processor (e.g., a CPU) connected to a memory (e.g., forstoring programming and maintaining a log of temperatures andpressures), a plurality of input-output interfaces through which the PLCreceives and sends data to and from external device, and acommunications interface for sending and receiving data to and fromremote devices, such as computers and mobile device (e.g., to facilitateremote control and remote access to the data and settings).

The PLC through its input-output interfaces is adapted to interact withexternal controllers, such as the motor 500 that controls the backflowvalve assembly 500 b (FIG. 3B) and the motors that control the settingson the gas valves and fluid valves. The control unit 100 and/or its PLC,in some implementations, includes a variable-frequency drive (VFD) forcontrolling the motor driving the pump 200, which is particularly usefulduring system startup and power-down.

The control unit 100 and/or its PLC may include one or more redundant orbackup modules to prevent total or partial shutdown of the system 1000due to hardware failure or power interruption. Emergency shutoffsequences and alarms may be activated in case of hardware failure,excess pressures or temperatures, or other types of system overloads.

FIG. 2A is a schematic view of a pressure vessel 300 suitable for usewith the example gas-injection systems described herein. The pressurevessel 300 receives a flow of the first solution from the pump 200through a connecting pipe 215. At the bottom of the pressure vessel 300,the first solution flows through a diverter pipe 310, as shown. Thediverter pipe 310 extends lengthwise, and in a substantially verticalorientation, from a base end at the bottom of the pressure vessel 300 toa distal end. The distal end of the diverter pipe 310 may be locatednear the center of the pressure vessel 300, to facilitate mixing. Asshown, the side wall of the diverter pipe 310 includes a plurality ofperforations 315. The first solution exits the pipe 310 through theperforations 315 and into the pressure vessel 300. The perforations 315may be any of a variety of sizes and shapes designed to facilitatemixing and injection.

The pressure vessel 300 includes a vent 330 for releasing the excessvolume of the ozone-rich gas. Instead of releasing this excessozone-rich gas into the atmosphere, the excess volume travels through avapor tube 150 into an ozone destructor 400, as shown in FIG. 1.

As shown in FIG. 2A, the pressure vessel 300 also includes a deflector320. The deflector 320 is sized and shaped, and positioned, toselectively inhibit the incoming flow of the first solution from flowinginto the vent 330. In this aspect, the deflector 320 prevents theincoming solution from spraying or otherwise flowing into the vent 330,which is designed to capture excess gas and not fluid. The fluid exitsthrough the outlet pipe 220. The deflector 320 is also sized and shaped,and positioned, to selectively inhibit the flow of ozone-rich gas fromentering the vent 330 too soon. The pressure vessel 300 is designed tohold the first solution, under pressure, for a selected duration, asdescribed herein.

FIG. 2B is a perspective illustration of an example deflector 320, whichis made from a metal plate, one-eighth inch thick and generallyrectangular in shape. The example deflector 320 is a curved plate withits four corners welded to the ceiling or upper surfaces inside thepressure vessel 300 near the vent 330. The excess flow of ozone-richgas, in this example, may flow around the side edges of the exampledeflector 320 and into the vent 330. The deflector 320, in someimplementations, may be made from another material, formed into othershapes and sizes, and may include perforations or other openings toallow the excess flow of ozone-rich gas to enter the vent 330. Thepressure inside the pressure vessel 300 is selected to facilitateadditional mixing and injection. When the selected pressure is exceeded,the excess flow of ozone-rich gas will enter the vent 330.

Referring again to FIG. 1, the system 1000, in some implementations,includes an ozone destructor 400 for capturing an excess volume of theozone-rich gas from the pressure vessel 300. This excess volume ischaracterized by its having not been infused into the first solution.The ozone destructor 400 includes a catalyst for convertingsubstantially all the ozone in the excess volume to oxygen, and anoutlet 401 for venting the oxygen (directly to the atmosphere, in someimplementations). The catalyst may be a compound such as manganesedioxide, copper oxide, or other suitable compounds, or mixtures thereof.The ozone destructor 400, in various implementations, may include aheater, one or more vanes or other structures for directing the flow ofgas through the chamber, filter media in addition to the catalyst, and afan for drawing the gas through the chamber and/or expelling the oxygenthrough the outlet 401. For systems in which the gas is not anozone-rich gas, the ozone destructor 400 may be replaced with anothertype of system for safely handling excess gas before it is released tothe atmosphere.

FIG. 3A is a cross-sectional illustration of a backflow valve assembly500 a with a manual control, located in the outlet pipe 220. Thebackflow valve assembly 500 a, in some implementations, includes ahandle 501 configured to lower and raise a blade 502 into the pipe 220to modify the flow of fluid therethrough and thereby generate a backflowpressure in the elements located upstream, as described herein. Theblade 502 may be constructed of a solid stainless-steel plate having athickness of between about one eighth and one quarter of an inch. Thesolid blade 502 is sized and shaped to fit between an upstream plate 503and a downstream plate 504. The plates 503, 504 include one or moredrilled holes or openings, as shown.

FIG. 3B is a cross-sectional illustration of a backflow valve assembly500 b with a motorized control, located in the outlet pipe 220. Thebackflow valve assembly 500 b, in this example, includes a motor 550connected to a shaft 560 that is configured to lower and raise a blade560 into the pipe 220 to modify the flow of fluid therethrough andthereby generate a backflow pressure in the elements located upstream,as described herein. The blade 560 may be constructed of a solidstainless-steel plate having a thickness of between about one eighth andone quarter of an inch. The solid blade 560 is sized and shaped to fitbetween an upstream plate 573 and a downstream plate 574. The plates573, 574 include one or more drilled holes or openings, as shown. Themotor 550 may be connected to and controlled by the control unit 100 orcontrolled separately.

Whether manual or motorized, the backflow valve assembly 500 a, 500 b isadjustable, in some implementations, to generate a desired amount ofbackflow pressure in the elements located upstream. As the backflowvalve assembly 500 a, 500 b is closed, the flow restriction increases,which in turn generates a higher backflow pressure. The backflowpressure increases the internal pressure inside the pressure vessel 300and prolongs the duration of time for mixing inside the pressure vessel300. The backflow pressure, to some extent, also affects the pressureand mixing time inside the mixing chamber 205 of the pump 200.

In another implementation, the backflow valve assembly 500 is notadjustable with a manual or motorized control. In this example, thebackflow valve assembly 500 is custom-made and includes one or moreinternal components designed to restrict or modify the flow of fluidthrough the valve and to thereby generate a backflow pressure in theelements located upstream, as described herein.

FIG. 4 is an illustration of a nozzle assembly 700 c according to someexample implementations. The nozzle assembly 700 c includes a threadedconnector 710 configured to attach to the outlet pipe 220. Like thepressure vessel 300 and the backflow valve assembly 500, the nozzleassembly 700 c generates a backflow pressure into the system, whichfacilitates the additional injection of nanobubbles in the elementslocated upstream. In this aspect, the size and shape of the nozzleassembly 700 c facilitates and helps maintain a consistent operatingpressure throughout the system 1000.

The valve body 702, as shown, defines one or more flow passages 720 influid communication between the fluid inlet (through connector 710) andone or more fluid outlets 725. The flow passages 720 are convergingtoward the fluid outlets 725. In other words, the cross-sectional areaof the flow passages 720 is decreasing as the fluid flows toward theoutlets 725. The converging shape of the flow passages 720 may be formedby any of a variety of nozzle elements and commercially availabledesigns. The converging shape of the flow passages 720 causes a rapidincrease in flow velocity and a rapid decrease in pressure. The rapidpressure drop causes at least a portion of the gas nanobubbles to bereleased into the fluid in the reservoir 10. The gas nanobubbles thatwere once dissolved in the second solution, as they pass through theconverging nozzle assembly 700 c, are released from the second solutionand injected into the fluid in the reservoir 10. This release of gasfacilitates the destruction of pollutants and other contaminants in thefluid. For implementations in which the gas is an ozone-rich gas and thefluid is contaminated water, the release of nanobubbles creates hydroxylradicals which are highly reactive and useful in destroying organiccompounds and other contaminants in water.

Applications of the methods and systems described herein are useful fordisinfecting bodies of water, such as lakes, wetlands, livestock wastepits, ballast water in watercraft, and wastewater ponds or tanks.Applications of the methods and systems described herein are useful fordisinfecting the air in a room or other bounded space, including thesurfaces, equipment, and other items in the room; for disinfectingmedical equipment instead of or in addition to autoclaving; and forsterilizing fruits, vegetables, and other perishable foods.

Although several implementations and embodiments have been describedherein, those of ordinary skill in art, with the benefit of theteachings of this disclosure, will understand and comprehend many otherembodiments and modifications for this technology. This disclosure isnot limited to the specific embodiments disclosed or discussed herein,and that may other embodiments and modifications are intended to beincluded within the scope of the description. Moreover, althoughspecific terms are occasionally used herein, such terms are used in ageneric and descriptive sense only and should not be construed aslimiting the systems and methods described.

What is claimed is:
 1. A method of removing pollutants from a fluid,comprising: circulating a fluid in and through a circuit of elementscomprising a reservoir, a pump comprising a mixing chamber, a pressurevessel, and one or more nozzles immersed in the reservoir; dissolving avolume of gas into the fluid from a gas supply in fluid communicationwith the mixing chamber; and spraying the fluid through the one or morenozzles and into the reservoir, wherein the one or more nozzles is sizedand shaped to release from the fluid at least a portion of the dissolvedvolume of gas into the reservoir.
 2. The method of claim 1, wherein theprocess of circulating the fluid continues until at least one of (a) adesired portion of the dissolved volume of gas is released from thefluid or (b) a desired quantity of pollutants is removed from the fluid.3. The method of claim 1, wherein the process of dissolving the volumeof gas into the fluid further comprises: delivering a first quantity ofgas from the gas supply to the mixing chamber, such that at least a partof the first quantity of gas becomes dissolved into the fluid.
 4. Themethod of claim 1, further comprising: converting ambient air with anoxygen concentrator into an oxygen-enriched gas; converting at least afirst portion of the oxygen-enriched gas with an ozone generator into anozone-rich gas, wherein the process of dissolving the volume of gascomprises injecting at least one of the oxygen-enriched gas or theozone-rich gas into the mixing chamber.
 5. The method of claim 1,further comprising: holding the fluid in the pressure vessel under aninternal pressure and for a selected duration, such that the pressurevessel facilitates the process of dissolving the volume of gas into thefluid.
 6. The method of claim 5, wherein the pressure vessel furthercomprises a fluid inlet, a fluid outlet, and a gas vent, the methodfurther comprising: inhibiting the fluid from entering the gas vent witha deflector; receiving the fluid through one or more perforationsdefined by a diverter pipe in fluid communication with the fluid inlet,such that the diverter pipe facilitates the process of holding the fluidin the pressure vessel; and locating the fluid outlet relative to thediverter pipe, such that the fluid outlet location facilitates theprocess of holding the fluid in the pressure vessel.
 7. The method ofclaim 1, further comprising: generating a backflow pressure in the fluidwith a backflow valve, such that the backflow valve facilitates theprocess of dissolving the volume of gas into the fluid.
 8. The method ofclaim 7, wherein the process of generating the backflow pressurecooperates with the one or more nozzles to facilitate the release of theportion of the dissolved volume of gas.
 9. The method of claim 1,further comprising: holding the fluid in the pressure vessel under aninternal pressure and for a selected duration; and generating a backflowpressure in the fluid with a backflow valve, such that the generatedbackflow pressure cooperates with the internal pressure to facilitatethe process of dissolving the volume of gas into the fluid.
 10. Themethod of claim 1, wherein the circuit of elements further comprises aVenturi injector in fluid communication with the gas supply, and whereinthe process of dissolving the volume of gas into the fluid furthercomprises: delivering a supplemental quantity of gas from the gas supplyto the Venturi injector.
 11. The method of claim 10, wherein the processof delivering the supplemental quantity of gas further comprises:creating a pressure differential within a lengthwise chamber of theVenturi injector, wherein the lengthwise chamber is sized and shaped todraw at least a portion of the supplemental quantity of gas into theVenturi injector.
 12. The method of claim 1, wherein the circuit ofelements further comprises a recirculation pipe controlled by arecirculation valve for recirculating a select portion of the fluid fromthe circuit to an inlet pipe located upstream relative to the mixingchamber, the method further comprising: controlling the circulation offluid through the recirculation pipe facilitates the process ofdissolving the volume of gas into the fluid.
 13. The method of claim 1,wherein each of the one or more nozzles comprises a nozzle body definingat least one flow passage and at least one outlet, the method furthercomprising: shaping the at least one flow passage to converge in sizetoward the at least one outlet, such that the converging shapefacilitates the release of the portion of the dissolved volume of gas.14. The method of claim 1, wherein the one or more nozzles comprises apair of nozzles spaced apart from one another and immersed in thereservoir to a depth, the method further comprising: selecting the depthto facilitate the release of the portion of the dissolved volume of gas.